We propose a system for adaptive streaming from multiple servers to a single receiver over separate network paths. Based on incoming packets, the receiver estimates the available bandwidth on every path and returns this information to the servers. An optimization algorithm is designed that enables the servers to independently partition the media packets among them according to the bandwidth information and such that the resulting video quality at the receiver is maximized. To this end, the algorithm takes advantage of a source pruning technique that preprocesses the media stream ahead of time. Simulation results demonstrate that the proposed streaming framework provides superior performance over a conventional transmission scheme that performs proportional packet scheduling based only on the available network bandwidth. Due to its low-complexity aspect, the framework is suitable for practical implementations of adaptive and efficient distributed streaming systems.